Operative Approach: Deltopectoral and Anterosuperior



Operative Approach: Deltopectoral and Anterosuperior


Yoav Rosenthal, MD

Young W. Kwon, MD, PhD



INTRODUCTION

Shoulder arthroplasty has been performed with high rates of patient satisfaction, decreased pain levels, and improved function to treat a variety of pathologies about the shoulder.1,2,3,4,5 Due to its efficacy, the prevalence of shoulder arthroplasty has almost doubled in the United States in less than 10 years.6

The deltopectoral approach and the anterosuperior approach have been the most commonly utilized approaches for shoulder arthroplasty. Both approaches may yield comparable clinical outcomes with a different complication profile. This chapter describes the two approaches from patient positioning to deep exposure, emphasizing on the surgical technique, advantages, and potential complications. Further information regarding the capsular release, subscapularis management, humerus and glenoid exposure can be found in the corresponding surgical technique chapters.


DELTOPECTORAL APPROACH

Historically, shoulder arthroplasty is performed through an anterior approach. The first shoulder arthroplasty was performed by Jules Emile Péan in 1893, using an anterior incision passing down vertically from the acromion, between the deltoid and the biceps.7 Subsequently, Arnold K. Henry described the extensile anterior approach in 1945.8 To the best of our knowledge, however, the first full description of the use of the anterior deltopectoral approach for shoulder arthroplasty was published by Charles S. Neer in 1963.9

The deltopectoral approach for the shoulder, which is considered as the “work-horse” of all shoulder approaches, is useful for various surgical indications (VIDEO 11.1). This approach utilizes an internervous plane between the axillary nerve on the lateral side and the medial and lateral pectoral nerves on the superficial medial side and the musculocutaneous nerve on the deep medial side. In addition, it provides wide exposure and excellent access to the glenohumeral joint.


Indications for Deltopectoral Approach



  • Shoulder arthroplasty


  • Revision shoulder arthroplasty


  • Anterior glenohumeral stabilization


  • Proximal humerus fracture open reduction and fixation


  • Septic joint irrigation and debridement


  • Tumor biopsy and excision


Advantages

The deltopectoral approach utilizes a true anatomic plane that is internervous, intermuscular, and atraumatic. Preservation of deltoid muscle integrity is paramount for successful outcome after the surgery. This is especially crucial for reverse shoulder arthroplasty, which is powered primarily by the deltoid muscle for active motion. The deltopectoral approach provides initial wide exposure and allows an extensile approach to the entire humerus, if necessary, for revision arthroplasty, fracture management, and tumor resection with subsequent reconstruction. Furthermore, this approach provides excellent exposure, especially to the superior, anterior, and inferior structures, eg, the inferior glenoid pole and humeral neck osteophytes. The versatile deltopectoral approach is suitable for all types of arthroplasty, regardless of the etiology or the presence of an intact rotator cuff. If indicated, it even provides access for a latissimus dorsi tendon transfer.10,11,12


Disadvantages

Despite its merits and popularity, the deltopectoral approach has several limitations. Since glenoid exposure depends on posterior retraction of the deltoid muscle, adequate glenoid exposure may be limited in muscular patients with a hypertrophied deltoid. Furthermore, the deltopectoral approach may offer limited access to posterior structures about the glenohumeral joint. For example, imbrication of posterior capsule during arthroplasty cases or isolation of the displaced greater tuberosity fragment in fracture cases can be challenging through the deltopectoral interval.10,11,12

Surprisingly, despite having the theoretical advantage of being an internervous approach, the deltopectoral was found to have a higher incidence of neurologic complications than the anterosuperior approach for anatomic shoulder arthroplasty.13 Comparing the two approaches,
Lynch and colleagues found neurologic complications involving the brachial plexus in 4.7% of the deltopectoral approach patients and 0% in the anterosuperior approach patients, none of which involved the axillary nerve.13







Dangers

Despite being relatively safe, several neurovascular structures are in close proximity and can be injured during the deltopectoral approach, either by a direct insult or indirectly by excessive traction. These include the cephalic vein, ascending branches of the anterior circumflex artery, axillary artery and vein, the musculocutaneous nerve, axillary nerve, and the brachial plexus (FIGURE 11.1).


Surgical Technique (Table 11.1)


Patient Positioning and Draping

The patient is placed in a “beach chair” position with the torso flexed in about 30° to 45°. At this angle, the venous pressure is reduced, and the arm may be comfortably manipulated for the humeral preparation. The head and neck should be secured in a designated headrest, and the trunk should be stabilized in order to accurately estimate the glenoid version during the procedure. In addition, the arm must be allowed to fully extend in order to provide complete humeral head and canal exposure. Prior to surgical preparation, the final positioning of the patient should be rechecked and secured as adjustments will be quite difficult after draping. For the majority of the procedure, the arm must be secured in various positions. This can be accomplished by a surgical assistant with or without the use of a padded surgical stand or with a commercially available arm holder (FIGURE 11.2).









Initial Incision Marking

The bony landmarks are palpated and marked. They include the acromion, clavicle, tip of the coracoid process, and the deltoid tuberosity of the humerus. The line for proposed surgical incision starts at the level of the clavicle and is extended distally through the tip of the coracoid process, aiming toward the deltoid tuberosity (or mid-humeral line) to the level of the axilla. This line should measure approximately 12 to 14 cm (FIGURE 11.3).


Superficial Dissection

While keeping tension on both sides of the line, the incision is carried out through the skin and the subcutaneous
tissue down to the deltopectoral fascia. After achieving hemostasis, lateral and medial skin flaps are developed, and appropriate retractors are placed. At this stage, the fat stripe, which envelops the cephalic vein, should be visible. The cephalic vein is exposed in its entirety about the deltopectoral interval (FIGURE 11.4). Caution should be taken while dissecting the vein as several branches drain into the main vessel both proximally and distally. Pending surgeon preference, the cephalic vein can be mobilized and retracted medially with the pectoralis or laterally with the deltoid. Since the cephalic vein drains more branches from the deltoid muscle, lateral retraction may provide fewer alterations to the natural blood blow. Alternatively, as the vein is more likely to be damaged during deltoid retraction for glenoid exposure, it may be better protected if it is retracted medially with the pectoralis. Clinically, there is no evidence to suggest that retraction of the vessel to either direction is superior.











At this stage, the directions of muscle fibers of the pectoralis and the deltoid should be clearly visible such that the intermuscular interval can be easily identified. If the deltopectoral interval is not immediately obvious, the coracoid process can be palpated as it typically marks the superior most portion of the interval. The interval is gently dissected to avoid damage to the muscle tissue, while small vascular branches (usually in the proximal and distal part of the interval) are cauterized to prevent bleeding. The subdeltoid and the subacromial spaces are mobilized to allow continuity between the two spaces. With any previous surgical procedures including shoulder arthroscopy, there may be significant residual scar tissue in this region. In such instances, it is generally more effective to identify the subacromial space and then extend the exposure distally to include the subdeltoid space. While mobilizing this space, it is also helpful to place the shoulder in slight flexion, abduction, and internal rotation to improve access. Subsequently, the mobilized deltoid is retracted laterally and the pectoralis major is retracted medially to expose the clavipectoral facia (FIGURE 11.5).


Deep Layer Exposure

The clavipectoral fascia is divided longitudinally up to the coracoacromial ligament. For additional exposure,
the coracoacromial ligament can be either partially or completely released. For anatomic shoulder arthroplasty, however, to maintain the integrity of the coracoacromial arch and prevent anterior superior escape of the humeral head, the ligament may need to be maintained.






The conjoint tendon (brachioradialis and short head of biceps) is identified, and its fascia is divided to allow mobilization. It should be noted, however, that the tendon must be mobilized with its associated muscle fibers, which are often just lateral to the tendon (FIGURE 11.6). By retracting the deltoid muscle laterally and the conjoint tendon (with the pectoralis major) medially, the entire glenohumeral joint can be exposed. The musculocutaneous nerve lies on the deep surface of the conjoint tendon about 5.6 cm (range 3.1-8.2 cm) distal to the tip of the coracoid process.14 However, its most proximal branch penetrates the coracobrachialis muscle at about 3.4 cm (range 2.38-4.3 cm) distal to the tip of the coracoid proces15 (FIGURE 11.7). Therefore, the retractor should be placed and secured proximally underneath the conjoint tendon in order to avoid injuring the nerve.